F-Droid
It would be great to see this Android app on F-Droid!
F-Droid is an Android app store specifically for free/libre open-source apps. It would be great if your app could be released there, as it is the number one for getting FLOSS Android apps for many people. F-Droid also builds all apps from source (optionally even reproducible), so downloads from there can be trusted.
The app developer FAQ or the quick start guide may help you to get started.
BTW a release on F-Droid could also bring some (more) popularity (in case that is intended), as it will show up in the app (new apps are featured there).
Also checked the Guardian Project F-Droid repository, it's also not there.